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The reactive dinitrogen sulfide molecule, N2S, has been confirmed by He I photoelectron spectroscopic measurements as a major product of the thermal decomposition of 5-phenyl-1,2,3,4-thiatriazole. The adiabatic ionization energy of N2S is 10.55 eV, and its spectrum is characterized by two sharp ionization bands assigned as the ground 2 (irs) and first excited 2 ( ) states of the N2S+ ion. A broad band is tentatively assigned to the second excited 2 ( ) ion state. Comparison with the spectrum of its stable analogue, OCS, indicates that the N-S bond is relatively weak, so that the S atom effects only small perturbations of the og and iru molecular orbitals of N2 within the linear N2S molecule. Molecular orbital calculations provide data in good agreement with these observations, including estimates of the geometry and vibration frequencies of N2S and N2S+. The photoelectron spectra also show that diatomic sulfur, S2, is produced in the thermal decomposition of 5-phenyl-1,2,3,4-thiatriazole, from which it is concluded that N2S is undergoing bimolecular decomposition. This confirms that N2S is not only just an unstable but also probably a highly reactive 1,3-dipole similar to diazomethane, CH2N2, and potentially useful in chemical synthesis.The highly reactive molecule, N2S, has recently been identified by IR spectroscopy and mass spectrometry as a product of the thermal decomposition of S-phenyl-l^.SA-thiatriazole.1 11This N-N was in spite of earlier work2•3 which had discounted this route for the thermal decomposition.3 While there had been no substantial 150°d ouble-hemispherical electrostatic-focussing type. The spectrometer

Fragmentation energetics and dynamics of fluorobenzeneAr n (n=1-3) clusters studied by mass analyzed threshold ionization spectroscopy Ultraviolet photoelectron spectra have been measured for argon clusters prepared in pulsed supersonic expansions of both pure and seeded mixtures of argon. The broad band spectra show structural features which relate to the degree of condensation and hence the mean cluster size obtained at different stagnation pressures. These are interpreted in terms of an ion-core hypothesis with diatomics-in-molecules calculations being used to simulate spectral features. The analysis shows that Ar 3+ cores are formed in the initial ionization process of very small clusters, with the Ar 11 core becoming dominant for all larger clusters and for the condensed state of argon.

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